Abstract: A method to promote the total system optimization of hydrotreating units by means of taking hot feed from upstream directly was introduced. Based on “Three-Link-Theory” energy structural model, by optimizing distillation towers, heat exchang network, furnace and compressors/pumps to realize upgrading the utilization of low grade heat from upstream hot feed, the fuel of furnace and the steam of reboiler were saved. From a case study of a 1.0 Mt/a diesel fuel hydrotreating unit in a SINOPEC refinery, it can be seen that a 38.9% reduction of energy consumption was obtained. This method could also be used to other downstream units for total optimization of energy conservation.

Key words: hot-feed, hydrotreating, energy conservation, process energy, optimization